In an electrostatic spraying apparatus, electric charge can be supplied to a surface of a liquid. When the repulsive forces within the liquid caused by the electric charge exceed the surface tension maintaining the surface of the liquid, the surface of the liquid can explosively disrupt to form small jets. In some applications, the small jets can break up into streams of charged liquid clusters in the form of nanodrops (liquid phase) or nanoparticles (solid phase formed by solidifying nanodrops). The resulting stream of nanodrops can be directed onto a surface of a target material or substrate, which over time, can form a film on the surface.
The charged nanodrops can collect on the surface and form a space charge build-up which can result in non-uniform applications of the multi-jet sprays of nanoparticles on the substrate. An electrically insulated substrate cannot efficiently transport charge away from its surface. Consequently, certain areas of the substrate's surface can accumulate the charge of the applied nanodrops. The accumulated charge can repel additional applications of nanodrops which can cause the non-uniform application of nanodrops on the substrate.
FIGS. 26-27, Tables 1-2, respectively, depict illustrations of possible embodiments of a liquid used by the apparatus of FIG. 1, 2, 17, or 18 for spray application on a substrate; and
FIG. 28, Table 3 depicts an illustrative embodiment of a PEDOT:PSS thin film sprayed on a glass substrate showing a measured thickness of 64 points distributed uniformly over the substrate.